Preparation of synthetic hydrocarbon lubricants

ABSTRACT

This disclosure concerns a process for preparing a synthetic hydrocarbon lubricant composition, said composition consisting essentially of a major amount of di-long-chain alkyl monocyclic aromatic hydrocarbons and a minor amount of trialkyl-substituted tetrahydronaphthalenes. The process comprises (a) alkylating an admixture of a major amount of mono-long chain alkyl monocyclic aromatic hydrocarbons and a minor amount of alkyl-substituted tetrahydronaphthalenes with linear mono-olefins containing six to 18 carbon atoms, using aluminum chloride or aluminum bromide as the catalyst, under severe reaction conditions and (b) recovering the desired product. In both the mono-long-chain alkyl aromatic and di-long-chain alkyl aromatic hydrocarbons, the long-chain alkyl groups are linear and contain six to 18 carbon atoms while the aromatic moiety is phenyl, tolyl, or xylyl.

United States Patent McGuire et al.

[63] Continuation-impart of Ser. No. 417,683. Nov. 26,

I974, abandoned.

[52] US. Cl. 252/59; 260/671 G [51] Int. Cl.'-'. ClOM 1/16; ClOM 3/lO;ClOM 5/08; ClOM 7/12 [58] Field of Search 252/59; 260/671 G [56]References Cited UNITED STATES PATENTS 3.775.325 ll/l973 Kerfoot et al252/59 5/l974 Krenowicz et al. 252/59 PREPARATION OF SYNTHETICHYDROCARBON LUBRICANTS Inventors: Stephen E. McGuire; John L.

Riddle; Gene E. Nicks; Oliver Carl Kerfoot, all of Ponca City, Okla;Carl D. Kennedy, Spartanburg, S.C.

Assignee: Continental Oil Company, Ponca City, Okla.

Filed: July 15, 1974 Appl. No.: 488,622

Related U.S. Application Data Primary E.\'aminerDelbert E. GantzAssistant E.\'aminerl. Vaughn Attorney, Agent, or FirmBayless E.Rutherford, Jr.

[ 5 7 ABSTRACT This disclosure concerns a process for preparing asynthetic hydrocarbon lubricant composition, said composition consistingessentially of a major amount of di-longchain alkyl monocyclic aromatichydrocarbons and a minor amount of trialkyl-substitutedtetrahydronaphthalenes. The process comprises (a) alkylating anadmixture of a major amount of mono-long chain alkyl monocyclic aromatichydrocarbons and a minor amount of alkyl-substitutedtetrahydronaphthalenes with linear mono-olefins containing six to 18carbon atoms, using aluminum chloride or aluminum bromide as thecatalyst, under severe reaction conditions and (b) recovering thedesired product. In both the monolong-chain alkyl aromatic anddi-long-chain alkyl aromatic hydrocarbons, the long-chain alkyl groupsare linear and contain six to 18 carbon atoms while the aromatic moietyis phenyl, tolyl, or xylyl.

18 Claims, No Drawings PREPARATION OF SYNTHETIC HYDROCARBON LUBRICANTSCROSS-REFERENCE TO RELATED APPLICATIONS The present application is acontinuation-in-part of Application Serial No. 417,683, filed November26, 1974 and now abandoned. I

BACKGROUND AND FIELD OF INVENTION This invention is concerned with thepreparation of a synthetic hydrocarbon lubricant composition havingphysical properties which render it particularly useful under lowtemperatures (-40F or lower).

Heretofore, various synthetic lubricants have been developed to improveupon petroleum-derived lubricants. For example, US. Pat. No. 3,173,965discloses dialkylbenzenes having properties rendering them useful aslubricants while US. Pat. No. 3,288,176 discloses a bottoms fractionderived from the condensation of a substantially straight chainparaffinic hydrocarbon with an aromatic hydrocarbon as being useful as alubricant. Among the advantages of synthetic lubricants, in general, areimproved viscosity and pour point properties.

Recently, it has been found that the pour point properties ofdialkylbenzenes can be improved by incorporating therein additionalquantitiesof higher alkylsubstituted tetrahydronaphthalenes, preferablyhigher trialkyl-substituted tetrahydronaphthalenes, as indicated in US.Pat. No. 3,598,739 to Sias. Such compositions, according to Sias, areformed by separately preparing the higher alkyl-substitutedtetrahydronaphthalenes and then physically blending them with thepreviously prepared dialkylbenzenes sufficient to bring the totalcontent of higher alkyl-substituted tetrahydronaphthalenes in the blendto a level whereby the improved pour point properties are achieved.Thus, while the composition blends have highly desirable properties, thetechnique by which they are formed suffers from the disadvantage ofrequiring separate preparation of the higher alkyl-substitutedtetrahydronaphthalenes which can be blended with the dialkylbenzenes toattain necessary levels of the tetrahydronaphthalene derivatives in thefinal composition blend.

Commonly assigned copending application Ser. No. 258,137, filed May 30,1972, and now US. Pat. No. 3,775,325, discloses a process for preparingcompositions of the general type disclosed in Sias. Briefly, the processof the copending application comprises alkylating a mixture of monoalkylaromatic hydrocarbons and alkyl-substituted tetrahydronaphthalenes witha chlorinated C -C linear hydrocarbon or a fraction containing such.

Our invention is an improvement 'over that of US. Pat. No. 3,775,325. Wehave found that use of linear mono-olefins as the alkylating agentprovides several advantages. In general, the 40F viscosities are better.

More specifically, the -40F viscosities using linear mono-olefins, ascompared to chlorinated paraffins, are from about 1,000 to 3,000centistokes better (i.e., lower). An improvement of 1,00'0 cs at 40F i'squite significant since the addition of additives to produce acompounded lubricant (e.g., a crankcase oil) usually results in 40Fviscosity of the product being about twice that of the base oil.Moreover, our process is more attractive economically because of betterselectivity to dialkylbenzenes and lower production of undesirablebranched paraffin by-products.

PRIOR ART While there is other prior art concerning synthetichydrocarbon lubricants, to our knowledge none of it is more pertinentthan that discussed in the immediate foregoing.

BRIEF SUMMARY OF THE INVENTION Broadly stated, thepresent invention isdirected to a process for preparing a synthetic hydrocarbonlubricantcomposition, said composition consisting essentially ofdilong-chain alkyl aromatic hydrocarbons, wherein the longchain alkylgroups are linear and contain six to about 18 carbon atoms, with thetotal number of carbon atoms in the alkyl groups being from 12 to 36,preferably from 20 to 28, and wherein the aromatic 'moiety is phenyl,tolyl, or xylyl and trialkylsubstituted tetrahydronaphthalenes,containing a total of about 18 to about 42 carbons, said processcomprisa. alkylating an alkylatable hydrocarbon feedstock comprising amixtureof mono-long-chain alkyl aromatic hydrocarbons, wherein thelong-chain alkyl group and the aromatic moiety correspond to that of thedi-long-chain alkyl aromatic'hydrocarbons, and alkyl-substitutedtetrahydronaphthalenes containing from 12 to 24 total carbon atoms, withlinear monoolefins containing six to 18 carbon atoms, using aluminumchloride or aluminum bromide as the catalyst, under severe reactionconditions, and

b. recovering the desired product by means such as fractionaldistillation.

The process results in (1) selective alkylation of the alkyl-substitutedtetrahydronaphthalenes over the monoalkaryls and (2) avproduct havingimproved properties. The'process also serves to increase the meta topara ratio of the dialkyl aromatic hydrocarbons produced.

DETAILED DESCRIPTION A Materials Used The alkylatable hydrocarbonfeedstock has two essential components: (a) mono-long-chain alkylaromatics and (b) alkyl-substituted tetrahydronaphthalenes containing 12to 24 total carbon atoms.

Suitable mono-long-chain alkyl aromatic hydrocarbons are represented bythe formula Ar-R wherein Ar is benzene, toluene, or xylene, butpreferably is benzene, and wherein R is a linear long-chain alkyl groupcontaining from about six to about 18 carbon atoms, preferably fromabout 10 to about 14 carbon atoms, and most preferably from about 12 toabout 14 carbon atoms. Usually the alkyl group is attached to thearomatic nucleus through a secondary carbon PERCENT BY WEIGHT SuitablePreferred Mono-Long-Chain Alkyl Aromatic Hydrocarbons 60-96 85-96Alkyl-Substituted Tetrahydronaphthalenes 2-30 2-10 Miscellaneous AlkylAromatic Compounds, Less Than 10 5 Suitable linear mono-olefins for usein our process contain from about six to about 18 carbon atoms,preferably from about to about 14 carbon atoms. The double bond in thelinear mono-olefins can be present in the a-position or can be randomlylocated in an internal position. Either pure materials or mixtures ofmaterials containing the designated number of carbon atoms can be used.The preparation of C C a-olefins and C C internal mono-olefins is wellknown. The a-olefins are particularly suitable for use in our process.The a-olefins which can be used are predominantly linear material butcan contain minor amounts (e.g., 2 to about 15 weight percent) ofbranched chain a-olefins. The branched chain a-olefins appear todeteriorate the physical properties of the product. In addition, itshould be mentioned that the linear mono-olefin alkylating agent cancontain paraffins of the same approximate molecular weight, which can beseparated from the alkylation product by distillation.

Suitable catalysts for use in our process include aluminum chloride,aluminum bromide, and mixtures thereof. Aluminum chloride is preferredbecause of relative cost.

It is well known in the alkylation art that use of aluminum chloride oraluminum bromide as the catalyst requires the use of a hydrogen-donorpromoter, such as water or hydrogen chloride. In many instances,sufficient water is present in situ in the materials used. The type andamount of promoter can be determined readily without undueexperimentation by any person skilled in this art.

Process Conditions The relative amounts of linear mono-olefin andalkylatable hydrocarbon feedstocks are as follows:

MOLES OLEFlN/MOLES AROMATIC FEEDSTOCK Suitable Preferred 1:l-l:l0122-115 An important feature of our process is the use of severereaction conditions. This can be accomplished by increasing the amountof catalyst or by use of higher temperatures; preferably, both featuresare used.

Expressed as amount of aluminum chloride or aluminum bromide per unitamount of linear mono-olefin, a suitable amount of aluminum chloride oraluminum bromide is from about 2 to about 10 weight percent, preferablyfrom about 3 to about 6 weight percent.

Preferably, the reaction is conducted using a temper ature in the rangeof about to about C. A temperature as high as C can be usedsatisfactorily. Use of a lower temperature (e.g., to 50C) is much lessdesirable because of the inferior low temperature physical properties ofthe product, particularly at comparable catalyst levels.

Knowing that the reaction is conducted under severe conditions. andknowing the amounts of catalyst and the reaction temperature range, asdescribed in the foregoing, any person skilled in this art can determinethe required reaction time. Suitable reaction times are in the range ofabout 5 to about 360 minutes, preferably about 15 to about 90 minutes.

Upon completion of the required time of reaction, the reaction isterminated. The alklyation reaction product is introduced into asuitable separator where the catalyst sludge is removed. Thecatalyst-free alkylation product is then treated to remove residualacidic components and impurities. This can be readily accomplished bywashing with water and/or a caustic solution or by percolating thealkylate through a bed of bauxite. Methods of purifying the crudealkylation reaction product are well known in the art.

After the alkylate reaction product has been treated in the mannerdescribed, it is then subjected to a fractional distillation in order toobtain the desired product, which is the bottoms fraction.

The cut point for separating the desired bottoms fraction is determinedby the molecular weight of the starting materials and by the physicalproperties desired in the bottoms fraction. In the preferred product, wehave found out points of about C to about 220C at 5 mm Hg can be used.In the most preferred product, a cut point of about -l90C at 5 mm Hg isused.

The Product of Our Invention The product of our invention has twoessential components: (a) dialkyl aromatic hydrocarbons and (b)trialkyl-substituted tetrahydronaphthalenes.

The dialkyl aromatic hydrocarbons are represented by the formula whereinAr is benzene, toluene, or xylene and wherein R is a linear alkyl groupcontaining from about six to about 18 carbon atoms, preferably about 10to about 14 carbon atoms, with the sum of the carbon atoms in thesealkyl groups being from about 12 to about 36, preferably from about 20to about 28.

The trialkyl-substituted tetrahydronaphthalenes can be represented bythe formula R EXAMPLES 1-7 These examples show a series of runs whereinthe temperature and amount of catalyst were varied. Ex- Rv amples 1-5used an admixture of monoalkylbenzenes 5 (MAB) and alkyl-substitutedtetrahydronaphthalenes (ATHN) having the following composition:

R2 MAB, 91* 95.8 ATHN, "/1 3.6

The MAB contained 53 percent C and 27 percent wherein R is a linearalkyl group containing from about C alkyl groups, with the remainderbeing predomisix to 18 carbon atoms and preferably from about 10 nantlyC16, C and C alkyl groups. to about 14 carbon atoms and wherein R and Rare Examples 6 and 7 used an admixture of monoalkyllinear alkyl groupscontaining from one to about l3 l5 benzenes (MAB) and alkyl-substitutedtetrahydrocarbon atoms each, with the sum of R and R being naphthalenes(ATHN) having the following composifrom about 2 to about 14. tion.

The amounts of the dialkyl aromatic hydrocarbons andtrialkyl-substituted tetrahydronaphthalenes in the M AB 96 6 product areas follows: ATHN, 3.0

S I b] P f d The MAB contained 42.6 percent C and 36.6 perd C re em centC no C with the remainder being predomi- DiLnng-Chain Alkyl nantly C Cand C f 75-95 The linear mono-olefins used were a mixture of CTr1alkyl-Subst1tuted Tetrahydronaphthalenes 54() 5-25 C12, C13, and C14a'olefins- All examples used a mole ratio of monoalkylbenzene mixture toa-olefins of 4:1. The catalyst used in all ex- The product of ourinvention usually hasa-40F visamples was A c Two i h percent f y of15,000 or lower- Preferably, the 4OOF 3O moter, based on AlCl was usedin all examples. The cosity is 12,000 cs or lower. More preferably, thetime was 0 minutes in all runs Viscosity does not exceed 10,000 AccordThe reaction temperature and other variables of the ingly, we can statethe following limits for the 40F process are Shown i T l vlscosity ofthe Product of our mvemlon' The physical properties and composition ofthe products are shown in Table II. The cut point for obtaining thebottoms product was 220C at 5 mm Hg.

Maximum Viscosity, cs TABLE 1 Suitable 15,000 Preferable 12.000 ExampleNo. l 2 3 4 5 6 7 More Preferable l0,000

a-o16nn, MOI Wt I85 185 177 175 175 181 181 AlCI 1 3 5 4 3 5 2 3 T C 7070 90 70 70 70 70 In order to dlsclose the nature of the present mvenemption still more clearly, the following examples will be (l)Based 0no1-olefin Table 11 Product Properties Example No. l 2 3 4 5 6 7Meta/para ratio 0.75 0.99 0.96 0.75 0.98 0.67 0.76 DAB( 1 76.6 78.0 78.376.3 77.2 71.6 74.2 'lTHN(2), 12.2 10.9 12.0 11.8 11.3 20.6 l8.4 PourPoint,

F 60 65 65 70 Viscosity Index 118 120 114 115 111 107 Viscosity, cs

40F 10,673 9,623 9,941 9,838 10,634 13,590 9,850 I00F 32.95 30.89 31.4731.27 32.81 35.56 30.40 210F 5.57 5.39 5.35 5.35 5.47 5.72 5.13

(l )Dialkylhenzenes (2 )Trialkyl-substituted tetrahydronaphthalenesgiven. It is to be understood that the invention is not to be limited tothe specific conditions or details set forth in these examples exceptinsofar as such limitations are specified in the appended claims.

EXAMPLES 8-1 0 This series of examples illustrates the improvement in--40F viscosity of the product prepared by our process using a-olefinsas the alkylating agent, as compared to the product of U.S. Pat. No.3,775,235, prepared by a process using chlorinated linear paraffins asthe alkylating agent.

Examples 8 and 9 illustrate our process while Example illustrates theprocess of US. Pat. No. 3,775,235.

In Examples 8 and 9 the admixtures of MAB and ATHN were the same as inExamples l-5. Also, in these examples the a-olefins (alkylating agent)were the same as in Example 3.

In Example 10 the chlorinated paraffin alkylating agent was a mixture ofchlorinated C -C paraffins. The paraffins were 24.5 mole percentchlorinated and contained 4.5 weight percent Cl.

The catalyst in all runs was 3 weight percent AlCl The mole ratio ofalkylate to alkylating agent was 4:1 in all runs.

The other conditions are shown in Table III below.

Table III Example No. 8 9 It) Time. min. lSO 60 90 Temp, "C 70 90 80 Thephysical properties and composition of the products are shown in TableIV. The cut point for obtaining (l)Dialkylbenzencs (2)Trialkyl-substitutcd telrahydronuphthalenes EXAMPLE I 1 In thisexample, a linear mono-olefin containing 10-14 carbon atoms and havingthe double bond randomly located in an internal position is used. Theinternal linear mono-olefins were prepared by catalytic dehydrogenationof linear C C paraffin. The conditions used are similar to those ofExample No. 2. The product has similar properties to those obtained inExample No. 2.

Thus, having described the invention in detail, it will be understood bythose skilled in the art that certain variations and modifications maybe made without departing from the spirit and scope of the invention asdefined herein and in the appended claims.

We claim:

1. A process for preparing a synthetic hydrocarbon lubricantcomposition, said composition consisting essentially of a major amountof di-long chain alkyl monocyclic aromatic hydrocarbon, wherein thelongchain alkyl groups are linear and contain six to about 18 carbonatoms and wherein the aryl moiety is phenyl, tolyl or xylyl, and a minoramount of trialkylsubstituted tetrahydronaphthalenes containing about l8to about 42 carbon atoms total, said process comprising: (a) alkylatingan alkylatable hydrocarbon feedstock comprising a mixture of a majoramount of mono-long-chain alkyl monocyclic aromatic hydrocarbons,wherein the long-chain alkyl group and the aromatic moiety correspond tothat of the di-long-chain alkyl aromatic hydrocarbons, and a minoramount of alkyl-substituted tetrahydronaphthalenes containing from 12 to24 carbon atoms, with from about 0.1 to about 1.0 mole of linearmono-olefins, containing about six to about l 8 carbon atoms, per moleof monolong-chain alkyl aromatic hydrocarbons and alkylsubstitutedtetrahydronaphthalenes, using as the catalyst from about to about 10weight percent aluminum chloride or aluminum bromide based on saidlinear mono-olefins, said alkylation being conducted at a temperature offrom 50 to about 100C and for a time in the range of about 5 to about360 minutes, and (b) recovering the desired product by distillation.

2. The process of claim 1 wherein the alkylatable hydrocarbon feedstockcontains about 60 to about 96 weight percent mono-long-chain monocyclicalkyl aromatic hydrocarbons and about 2 to about 30 weight percentalkyl-substituted tetrahydronaphthalenes.

3. The process of claim 2 wherein the catalyst is aluminum chloride.

4. The process of claim 3 wherein the amount of catalyst is about 3 toabout 6 weight percent.

5. The process of claim4 wherein the temperature is about to about C.

6. The process of claim 5 wherein the linear monoolefins contain fromabout 10 to about 14 carbon atoms. j

7. The process of claim 1 wherein the linear monoolefins are a-olefins.

8. The process of claim 6 wherein the linear monoolefins are a-olefiris.4

9. A process for preparing a synthetic hydrocarbon lubricantcomposition, said composition consisting essentially of a major amountof di-alkylbenzenes, wherein the alkyl groups are linear and containfrom about 10 to about 14 carbon atoms and a minor amount oftrialkylsubstituted tetrahydronaphthalenes containing 26 to 34 totalcarbon atoms, said process comprising: (a) alkylating an alkylatablehydrocarbon feedstock comprising a mixture of a major amount of linearmono-C C alkylbenzenes and a minor amount of alkyl-substitutedtetrahydronaphthalenes, containing from 16 to 20 total carbon atoms,with from about 0.1 to about 1.0 mole of linear mono-olefins, containingabout 10 to about 14 carbon atoms, per mole of monoalkylbenzenes andalkyl-substituted tetrahydronaphthalenes, using as the catalyst fromabout 2 to about 10 weight percent, based on said linear monoolefins,aluminum chloride or aluminum bromide, said alkylation being conductedat a temperature of from 70 to about 90C and for a time in the range ofabout 5 to about 360 minutes, and (b) recovering the desired productby.distillation.

10. The process of claim 9 wherein the alkylatable hydrocarbon feedstockcontains about 60 to about 96 weight percent mono-C, C, alkylbenzenesand about 2 to about 30 weight percent alkyl-substitutedtetrahydronaphthalenes.

11. The processof claim 10 wherein the catalyst is aluminum chloride.

12. The process of claim 11 wherein the amount of linear mono-olefins isfrom about 0.2 to about 0.5 catalyst is about 3 to about 6 weightpercent. moles per mole of monoalkylbenzenes and alkyl- 13. The processof claim 12 wherein the alkyl groups SubstitutedtetrahydrOnmahthalenesof said mono-alkylbenzene and saiddi-alkylbenzenes contain from about 12 to about 14 carbon atoms.

14. The recess of claim 13 wherein the alk latable hydrocarbgn feedstockcontains from abouty 85 to 17. The process of claim 13 wherein thelinear monoabout 96 weight percent mono-alkylbenzenes and from Olefinsare a'olefins' about 2 to about weight percent alkyl substituted 18. Theprocess of claim 15 wherein the linear monotetrahydronaphthalenes. 10Olefins are 15. The process of claim 14 wherein the amount of 16. Theprocess of claim 9 wherein the linear monoolefins are a-olefins-

1. A PROCESS FOR PREPARING A SYNTHETIC HYDROCARBON LUBRICANTCOMPOSITION, SAID COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR AMOUNTOF DI-LONG CHAIN ALKYL MONOCYCLIC AROMATIC HYDROCARBON, WHEREIN THELONG-CHAIN ALKYL GROUPS ARE LINEAR AND CONTAIN SIX TO ABOUT 18 CARBONAND WHEREIN THE ARYL MOIETY IS PHENYL, TOLYL OR XYLYL AND A MINORAMOUNTOF TRIALKYLSUBSTITUTED TETRAHYDRONAPHTHALENESS CONTAINING ABOUT 18 TOABOUT 42 CARBON ATONS TOTAL, SAID PROCESS COMPRISING: (A) ALKYLATING ANALKYALATABLE HYDROCARBON FEEDSTOCK COMPRISING A MIXTURE OF A MAJORAMOUNT OF MONO-LONG-CHAIN ALKYL MONOCYCLIC AROMATIC HYDROCARBONS,WHEREIN THE LONG-CHAIN ALKYL GROUP AND THE AROMATIC MOIETY CORRESPOND TOTHAT OF THE DILONG-CHAN ALKYL AROMATIC HYDROCARBONS, AND A MINOR AMOUNTOF ALKYL-SUBSITIUTED TETRAHYDRONAPHTHALENES CONTAINING FROM 12 TO 24CARBON ATOMS, WITH ABOUT 0.1 TO ABOUT 1.0 MOLE OF LINEAR MONO-OLEFINS,CONTAINING ABOUT SIX TO ABOUT 18 CARBON ATOMS, PER MOLE OFMONO-LONG-CHAIN ALKYL AROMATIC HYDROCARBONS AND ALKYL-SUBSTITUTEDTETRAHYDRONAPHALENES, USING AS THE CATALYST FROM ABOUT 2 TO ABOUT 10WEIGHT PERCNET ALUMINUM CHLORIDE OR ALUMINUM BROMIDE BASED ON SAIDLINEAR MONO-OLEFINS, SAID ALKYLATION BEING CONDUCTED AT A TEMPERATURN OFFROM 50* TO ABOUT 100*C AND FOR A TIME IN THE RANGE OF ABOUT 5 TO ABOUT360 MINUTES, AND (B) RECOVERIN THE DESIRED PRODUCT BY DISTILLATION. 2.The process of claim 1 wherein the alkylatable hydrocarbon feedstockcontains about 60 to about 96 weight percent mono-long-chain monocyclicalkyl aromatic hydrocarbons and about 2 to about 30 weight percentalkyl-substituted tetrahydronaphthalenes.
 3. The process of claim 2wherein the catalyst is aluminum chloride.
 4. The process of claim 3wherein the amount of catalyst is about 3 to about 6 weight percent. 5.The process of claim 4 wherein the temperature is about 70* to about90*C.
 6. The process of claim 5 wherein the linear mono-olefins containfrom about 10 to about 14 carbon atoms.
 7. The process of claim 1wherein the linear mono-olefins are Alpha -olefins.
 8. The process ofclaim 6 wherein the linear mono-olefins are Alpha -olefins.
 9. A processfor preparing a synthetic hydrocarbon lubricant composition, saidcomposition consisting essentially of a major amount ofdi-alkylbenzenes, wherein the alkyl groups are linear and contain fromabout 10 to about 14 carbon atoms and a minor amount oftrialkyl-substituted tetrahydronaphthalenes containing 26 to 34 totalcarbon atoms, said process comprising: (a) alkylating an alkylatablehydrocarbon feedstock comprising a mixture of a major amount of linearmono-C10-C14-alkylbenzenes and a minor amount of alkyl-substitutedtetrahydronaphthalenes, containing from 16 to 20 total carbon atoms,with from about 0.1 to about 1.0 mole of linear mono-olefins, containingabout 10 to about 14 carbon atoms, per mole of monoalkylbenzenes andalkyl-substituted tetrahydronaphthalenes, using as the catalyst fromabout 2 to about 10 weight percent, based on said linear mono-olefins,aluminum chloride or aluminum bromide, said alkylation being conductedat a temperature of from 70* to about 90*C and for a time in the rangeof about 5 to about 360 minutes, and (b) recovering the desired productby distillation.
 10. The process of claim 9 wherein the alkylatablehydrocarbon feedstock contains about 60 to about 96 weight percentmono-C10-C14 alkylbenzenes and about 2 to about 30 weight percentalkyl-substituted tetrahydronaphthalenes.
 11. The process of claim 10wherein the catalyst is aluminum chloride.
 12. The process of claim 11wherein the amount of catalyst is about 3 to about 6 weight percent. 13.The process of claim 12 wherein the alkyl groups of saidmono-alkylbenzene and said di-alkylbenzenes contain from about 12 toabout 14 carbon atoms.
 14. The process of claim 13 wherein thealkylatable hydrocarbon feedstock contains from about 85 to about 96weight percent mono-alkylbenzenes and from about 2 to about 10 weightpercent alkyl-substituted tetrahydronaphthalenes.
 15. The process ofclaim 14 wherein the amount of linear mono-olefins is from about 0.2 toabout 0.5 moles per mole of monoalkylbenzenes and alkyl-substitutedtetrahydronaphthalenes.
 16. The process of claim 9 wherein the linearmono-olefins are Alpha -olefins.
 17. The process of claim 13 wherein thelinear mono-olefins are Alpha -olefins.
 18. The process of claim 15wherein the linear mono-olefins are Alpha -olefins.